[Nucleotide-dependent degradation of nucleic acids by DNA and RNA polymerases]

In this review we summarize the current knowledge about recently discovered reactions of nucleotide-dependent nucleic acid degradation catalyzed by DNA and RNA polymerases. These reactions consist in the excision of the 3'-nucleotide of nascent DNA or RNA chain in the presence of non-complementary r/dNTPs. In the case of DNA polymerases the dinucleoside-5',5"-tetraphosphate as a product of the reaction is formed. In contrast, in the case of RNA polymerases non-complementary r/dNTPs stimulate 3'-->5' exonuclease degradation of RNA transcript. The possible role of these reactions in fidelity of DNA and RNA synthesis, in resistance of HIV reverse transcriptase towards nucleoside inhibitors is discussed.